Techniques  for timing advance group per subset of synchronization signal blocks in a wireless communication system

ABSTRACT

Aspects described herein relate to identifying a timing advance group (TAG) for a second remote radio header (RRH) that is different from a first RRH, the TAG associated with a timing advance (TA) offset, wherein the first RRH and the second RRH are associated with a serving cell, switching from the first RRH to the second RRH in accordance with the TAG and the associated TA offset, and transmitting, on an uplink communication channel, data to the second RRH.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of U.S. Provisional Application Ser.No. 62/965,699, entitled “TECHNIQUES FOR TIMING ADVANCE GROUP PER SUBSETOF SYNCHRONIZATION SIGNAL BLOCKS IN A WIRELESS COMMUNICATION SYSTEM” andfiled on Jan. 24, 2020, which is expressly incorporated by referenceherein in its entirety.

BACKGROUND

Aspects of the present disclosure relate generally to wirelesscommunication systems, and more particularly, to providing cell mobilitybased on a timing advance group (TAG) per subset of synchronizationsignal blocks (SSBs).

Wireless communication systems are widely deployed to provide varioustypes of communication content such as voice, video, packet data,messaging, broadcast, and so on. These systems may be multiple-accesssystems capable of supporting communication with multiple users bysharing the available system resources (e.g., time, frequency, andpower). Examples of such multiple-access systems include code-divisionmultiple access (CDMA) systems, time-division multiple access (TDMA)systems, frequency-division multiple access (FDMA) systems, andorthogonal frequency-division multiple access (OFDMA) systems, andsingle-carrier frequency division multiple access (SC-FDMA) systems.

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. For example, a fifth generation (5G)wireless communications technology (which can be referred to as NR) isenvisaged to expand and support diverse usage scenarios and applicationswith respect to current mobile network generations. In an aspect, 5Gcommunications technology can include: enhanced mobile broadbandaddressing human-centric use cases for access to multimedia content,services and data; ultra-reliable-low latency communications (URLLC)with certain specifications for latency and reliability; and massivemachine type communications, which can allow a very large number ofconnected devices and transmission of a relatively low volume ofnon-delay-sensitive information.

For example, for various communications technology such as, but notlimited to NR, some implementations may increase transmission speed andflexibility but also transmission complexity. Thus, improvements inwireless communication operations may be desired.

SUMMARY

The following presents a simplified summary of one or more aspects inorder to provide a basic understanding of such aspects. This summary isnot an extensive overview of all contemplated aspects, and is intendedto neither identify key or critical elements of all aspects nordelineate the scope of any or all aspects. Its sole purpose is topresent some concepts of one or more aspects in a simplified form as aprelude to the more detailed description that is presented later.

An example implementation includes a method of wireless communicationsat a user equipment (UE), including identifying a timing advance group(TAG) for a second remote radio header (RRH) that is different from afirst RRH, the TAG associated with a timing advance (TA) offset, thefirst RRH and the second RRH are associated with a serving cell. Themethod further includes switching from the first RRH to the second RRHin accordance with the TAG and the associated TA offset. The methodfurther includes transmitting, on an uplink communication channel, datato the second RRH.

A further example implementation includes an apparatus for wirelesscommunications comprising a memory and at least one processor incommunication with the memory. The at least one processor may beconfigured to identify a TAG for a second RRH that is different from afirst RRH, the TAG associated with a TA offset, the first RRH and thesecond RRH are associated with a serving cell. The at least oneprocessor may further be configured to switch from the first RRH to thesecond RRH in accordance with the TAG and the associated TA offset. Theat least one processor may further be configured to transmit, on anuplink communication channel, data to the second RRH.

An additional example implementation includes an apparatus for wirelesscommunications. The apparatus may include means for identifying a TAGfor a second RRH that is different from a first RRH, the TAG associatedwith a TA offset, the first RRH and the second RRH are associated with aserving cell. The apparatus further includes means for switching fromthe first RRH to the second RRH in accordance with the TAG and theassociated TA offset. The apparatus further includes means fortransmitting, on an uplink communication channel, data to the secondRRH.

A further example implementation includes computer-readable mediumstoring computer code executable by a processor for wirelesscommunications at a network entity comprising code for identifying a TAGfor a second RRH different from a first RRH, the TAG associated with aTA offset and the first RRH and the second RRH are associated with aserving cell, switching from the first RRH to the second RRH inaccordance with the TAG and the associated TA offset, and transmitting,on an uplink communication channel, data to the second RRH.

In some implementations, switching from a first RRH to a second RRH at acell may include communicating with the cell using beams of the secondRRH and not beams of the first RRH.

In some implementations, the first RRH may be associated with adifferent TAG and associated TA offset that is different from the TAGassociated with the TA offset of the second RRH.

In some implementations, the first RRH may be associated with a firstsubset of RSs and the second RRH is associated with a second subset ofRSs, and wherein the second subset of RSs may be associated with the TAGand the first subset of RSs is associated with the different TAG.

In some implementations, switching from the first RRH to the second RRHmay include switching from a first set of beams associated with thefirst RRH to a second set of beams associated with the second RRH, thesecond set of beams are quasi co-located with the second subset of RSsof the TAG.

In some implementations, the method may further include receiving, on adownlink communication channel, DCI or a MAC CE indicating one or bothof the first RRH or the second RRH to serve the UE.

In some implementations, the method may further include performinguplink TA measurement for both the first RRH and the second RRH, andupdating the TAG and TA offset of the second RRH and the different TAGand TA offset of the first RRH.

In some implementations, the TAG for the second RRH may correspond to amost recently received TAG for the second RRH.

In some implementations, the data may be transmitted on the uplinkcommunication channel based on the most recently received TAG for thesecond RRH.

In some implementations, the RSs may correspond to at least one of a SSBreference signal, a channel state information reference signal, orpositioning reference signal.

In some implementations, the method may further include receiving a DCIor MAC CE indicating one or both of a number of cells or PCIs, thenumber of cells or PCIs are associated with one or both of a servingcell or non-serving cell.

An example implementation includes a method of wireless communicationsat a serving cell having a first RRH and a second RRH. The methodincludes transmitting, on a downlink communication channel, a first TAGand associated TA offset for the second RRH to a UE. The method furtherincludes detecting a switch of the UE from the first RRH to the secondRRH. The method further includes receiving, on an uplink communicationchannel, data from the second RRH.

A further example implementation includes an apparatus having a firstRRH and a second RRH for wireless communications comprising a memory andat least one processor in communication with the memory. The at leastone processor may be configured to transmit, on a downlink communicationchannel, a first TAG and associated TA offset for the second RRH to aUE. The at least one processor may be configured to detect a switch ofthe UE from the first RRH to the second RRH. The at least one processormay be configured to receive, on an uplink communication channel, datafrom the second RRH.

An additional example implementation includes an apparatus having afirst RRH and a second RRH for wireless communications. The apparatusmay include means for transmitting, on a downlink communication channel,a first TAG and associated TA offset for the second RRH to a UE. Theapparatus further includes means for detecting a switch of the UE fromthe first RRH to the second RRH. The apparatus further includes meansfor receiving, on an uplink communication channel, data from the secondRRH.

A further example implementation includes computer-readable mediumstoring computer code executable by a processor for wirelesscommunications at a network entity comprising code for transmitting, ona downlink communication channel, a first TAG and associated TA offsetfor the second RRH to a UE, detecting a switch of the UE from the firstRRH to the second RRH, and receiving, on an uplink communicationchannel, data from the second RRH.

In some implementations, the method may further include transmitting asecond TAG and associated TA offset for the second RRH to the UEfollowing transmission of the first TAG.

In some implementations, detecting the switch from the first RRH to thesecond RRH may include detecting the switch in accordance with thesecond TAG and associated TA offset for the second RRH, the second TAGand associated TA offset corresponding to a most recent TAG.

In some implementations, the first RRH may be associated with a firstsubset of RSs and the second RRH may be associated with a second subsetof RSs, and wherein the second subset of RSs is associated with the TAGand the first subset of RSs is associated with the different TAG.

In some implementations, the RSs may correspond to at least one of a SSBreference signal, a channel state information reference signal, orpositioning reference signal.

In some implementations, the method may include transmitting, on thedownlink communication channel, DCI or a MAC CE indicating one or bothof the first RRH or the second RRH to serve the UE.

In some implementations, the method may include transmitting a DCI orMAC CE indicating one or both of a number of cells or PCIs, the numberof cells or PCIs are associated with one or both of a serving cell ornon-serving cell.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosed aspects will hereinafter be described in conjunction withthe appended drawings, provided to illustrate and not to limit thedisclosed aspects, wherein like designations denote like elements, andin which:

FIG. 1 illustrates an example of a wireless communication system, inaccordance with various aspects of the present disclosure;

FIG. 2 is a block diagram illustrating an example of a network entity(also referred to as a base station), in accordance with various aspectsof the present disclosure;

FIG. 3 is a block diagram illustrating an example of a user equipment(UE), in accordance with various aspects of the present disclosure;

FIG. 4 is a flowchart of a method of wireless communication at a UE, andmore specifically a method of UE intra-cell mobility based on a timingadvance group (TAG) per subset of synchronization signal blocks (SSBs);

FIG. 5 is a flowchart of a method of wireless communication at a networkentity, and more specifically of a network supported intra-cell mobilitybased on a TAG per subset of SSBs; and

FIG. 6 is a block diagram illustrating an example of a MIMOcommunication system including a base station and a UE, in accordancewith various aspects of the present disclosure.

DETAILED DESCRIPTION

Various aspects are now described with reference to the drawings. In thefollowing description, for purposes of explanation, numerous specificdetails are set forth in order to provide a thorough understanding ofone or more aspects. It may be evident, however, that such aspect(s) maybe practiced without these specific details.

The described features generally relate to reporting of timingdifference for different synchronization signal blocks (SSBs) in fifthgeneration new radio (5G NR). For example, multi-beam operation may beenhanced by targeting frequency range two (FR2) while also beingapplicable to FR1. In an example, these enhancements may includeidentifying and specifying features to facilitate more efficient (lowerlatency and overhead) downlink or uplink (DL/UL) beam management tosupport higher intra- and layer 1 or layer 2 (L1/L2) centric inter-cellmobility and/or a larger number of configured transmission configurationindicator (TCI) states. This example may include common beam for dataand control tran1smission/reception for DL and UL, especially forintra-band carrier aggregation (CA), unified TCI framework for DL and ULbeam indication, and enhancement on signalling mechanisms for the abovefeatures to improve latency and efficiency with more usage of dynamiccontrol signalling (as opposed to radio resource control (RRC)). Inanother example, these enhancements may include identifying andspecifying features to facilitate UL beam selection for UEs equippedwith multiple panels, considering UL coverage loss mitigation due tomaximum permissible exposure (MPE), based on UL beam indication with theunified TCI framework for UL fast panel selection.

In an aspect, the support for multi-TRP deployment may be enhanced bytargeting both FR1 and FR2. For example, these enhancements may includeidentifying and specifying features to improve reliability androbustness for channels other than physical downlink shared channel(PDSCH) (that is, physical downlink control (PDCCH), physical uplinkshared channel (PUSCH), and physical uplink control channel (PUCCH))using multi-transmission reception points (TRP) and/or multi-panel, withRelease 16 reliability features as the baseline. These enhancements mayfurther include identifying and specifying quasi-co-location(QCL)/TCI-related enhancements to enable inter-cell multi-TRPoperations, assuming multi-downlink control information (DCI) basedmulti-PDSCH reception. These enhancements may further include evaluatingand, if needed, specifying beam-management-related enhancements forsimultaneous multi-TRP transmission with multi-panel reception.

Additionally, these enhancements may include enhancements to supporthigh speed train (HST)-single frequency network (SFN) deploymentscenario. This example may include identifying and specifyingsolution(s) on QCL assumption for demodulation reference signal (DMRS)(e.g. multiple QCL assumptions for the same DMRS port(s), targetingDL-only transmission), and/or evaluating and, if the benefit overRelease 16 HST enhancement baseline is demonstrated, specifyingQCL/QCL-like relation (i.e., including applicable type(s) and theassociated requirement) between DL and UL signal by reusing the unifiedTCI framework.

The present disclosure relates generally to current issues of L1/L2based mobility with SSB split among remote radio headers (RRH). Forexample, in an aspect, each serving cell may have multiple RRHs, whichshare the same SSB ID space. Each RRH may transmit a sub-set of SSB IDsbut with a same physical cell identity (PCI) for the serving cell.Accordingly, when a UE switches among RRHs within the same serving cell,propagation delay to different RRHs may be different. However, inRelease 15/16, each serving cell belongs to a single timing advancegroup (TAG), which has a single TA offset value. Therefore, when the UEswitches RRH, a gNB may have to trigger PDCCH order for UL TAmeasurement and send the updated TA offset to the UE. This may increaseRRH switching latency and overhead.

In one implementation, the present aspects provide a UE that maydetermine to switch from a first RRH to a second RRH. The UE may furtheridentify a TAG for the second RRH, the TAG associated with a TA offset,the first RRH and the second RRH are associated with a serving cell. TheUE may further switch from the first RRH to the second RRH in accordancewith the TAG and the associated TA offset. The UE may further transmit,on an uplink communication channel, data to the second RRH.

In another implementation, the present aspects also provide a servingcell having a first RRH and a second RRH. The serving cell may transmit,on a downlink communication channel, a first TAG and associated TAoffset for the second RRH to a UE. The serving cell may further detect aswitch of the UE from the first RRH to the second RRH. The serving cellmay further receive, on an uplink communication channel, data from thesecond RRH.

In some aspects, an RRH may be a remote radio transceiver that connectsto an operator radio control panel via electrical or wireless interface.More specifically, the RRH may be a physical unit within a base stationcontaining the base station's RF circuitry plus analog-to-/digital ordigital-to-analog converters and up/down converters.

The described features will be presented in more detail below withreference to FIGS. 1-6.

As used in this application, the terms “component,” “module,” “system”and the like are intended to include a computer-related entity, such asbut not limited to hardware, software, a combination of hardware andsoftware, or software in execution. For example, a component may be, butis not limited to being, a process running on a processor, a processor,an object, an executable, a thread of execution, a program, and/or acomputer. By way of illustration, both an application running on acomputing device and the computing device can be a component. One ormore components can reside within a process and/or thread of executionand a component can be localized on one computer and/or distributedbetween two or more computers. In addition, these components can executefrom various computer readable media having various data structuresstored thereon. The components can communicate by way of local and/orremote processes such as in accordance with a signal having one or moredata packets, such as data from one component interacting with anothercomponent in a local system, distributed system, and/or across a networksuch as the Internet with other systems by way of the signal. Softwareshall be construed broadly to mean instructions, instruction sets, code,code segments, program code, programs, subprograms, software modules,applications, software applications, software packages, routines,subroutines, objects, executables, threads of execution, procedures,functions, etc., whether referred to as software, firmware, middleware,microcode, hardware description language, or otherwise.

Techniques described herein may be used for various wirelesscommunication systems such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, andother systems. The terms “system” and “network” may often be usedinterchangeably. A CDMA system may implement a radio technology such asCDMA2000, Universal Terrestrial Radio Access (UTRA), etc. CDMA2000covers IS-2000, IS-95, and IS-656 standards. IS-2000 Releases 0 and Aare commonly referred to as CDMA2000 1X, 1X, etc. IS-656 (TIA -656) iscommonly referred to as CDMA2000 1×EV-DO, High Rate Packet Data (HRPD),etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. ATDMA system may implement a radio technology such as Global System forMobile Communications (GSM). An OFDMA system may implement a radiotechnology such as Ultra Mobile Broadband (UMB), Evolved UTRA (E-UTRA),IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDM™, etc.UTRA and E-UTRA are part of Universal Mobile Telecommunication System(UMTS). 3GPP Long Term Evolution (LTE) and LTE-Advanced (LTE-A) are newreleases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, andGSM are described in documents from an organization named “3rdGeneration Partnership Project” (3GPP). CDMA2000 and UMB are describedin documents from an organization named “3rd Generation PartnershipProject 2” (3GPP2). The techniques described herein may be used for thesystems and radio technologies mentioned above as well as other systemsand radio technologies, including cellular (e.g., LTE) communicationsover a shared radio frequency spectrum band. The description below,however, describes an LTE/LTE-A system for purposes of example, and LTEterminology is used in much of the description below, although thetechniques are applicable beyond LTE/LTE-A applications (e.g., to fifthgeneration (5G) NR networks or other next generation communicationsystems).

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in other examples.

Various aspects or features will be presented in terms of systems thatcan include a number of devices, components, modules, and the like. Itis to be understood and appreciated that the various systems can includeadditional devices, components, modules, etc. and/or may not include allof the devices, components, modules etc. discussed in connection withthe figures. A combination of these approaches can also be used.

FIG. 1 is a diagram illustrating an example of a wireless communicationssystem and an access network 100. The wireless communications system(also referred to as a wireless wide area network (WWAN)) can includebase stations 102, UEs 104, an Evolved Packet Core (EPC) 160, and/or a5G Core (5GC) 190. The base stations 102, which may also be referred toas network entities, may include macro cells (high power cellular basestation) and/or small cells (low power cellular base station). The macrocells can include base stations. The small cells can include femtocells,picocells, and microcells. In an example, the base stations 102 may alsoinclude gNBs 180, as described further herein.

In one example, some nodes such as base station 102/gNB 180, may have amodem 240 and communicating component 242 for supporting cell mobilitybased on a TAG per subset of SSBs, as described herein. Though a basestation 102/gNB 180 is shown as having the modem 240 and communicatingcomponent 242, this is one illustrative example, and substantially anynode may include a modem 240 and communicating component 242 forproviding corresponding functionalities described herein.

In another example, some nodes such as UE 104 of the wirelesscommunication system may have a modem 340 and communicating component342 for intra or inter cell mobility based on a TAG per subset of SSBs,as described herein. Though a UE 104 is shown as having the modem 340and communicating component 342, this is one illustrative example, andsubstantially any node or type of node may include a modem 340 andcommunicating component 342 for providing corresponding functionalitiesdescribed herein.

For example, the communicating components 242 and 342 may be configuredto support inter and/or intra cell mobility based on a TAG per subset ofSSBs. Specifically, each SSB or subset of SSBs of a serving cell (e.g.,base station 102/gNB 180) can be associated with one TAG. The TA offsetper TAG may be continuously updated, regardless if the UE 104 is servedby corresponding SSB(s) (RRH(s)) or not. Further, if the UE 104 isswitched to the beams quasi co-located (QCLed) with SSB(s) in a new TAG,the UE 104 may use the latest TA offset for that TAG for uplinktransmission. So, the forgoing may save the uplink TA measurement andsending of the updated TA offset to UE 104.

In some aspects, the SSB concept can also extend to other cell definingreference signals (RSs), including a channel state information referencesignal (CSI-RS) or a PRS (positioning RS). In some aspects related toL1/L2 based mobility via PCI selection, each cell may have a singlephysical cell identifier (PCI). The DCI/MAC-CE can select which cell(s)or PCI(s) to serve the UE 104. Here, the cell can include servingcell/PCI, or non-serving cell/PCI, or both.

In another implementation related to L1/L2-centric inter-cell mobility,a number of operation modes may be defined. In a first example, eachserving cell may one PCI and can have multiple physical cell sites, e.g.RRH. Each RRH may transmit a different set of SSB IDs but with same PCIfor this serving cell. The DCI/MAC-CE can select which RRH(s) orcorresponding SSBs to serve the UE 104 based on RSRP per reported SSBID. In a second example, each serving cell can be configured withmultiple PCIs. Each RRH of the serving cell can use one PCI configuredfor this serving cell and can transmit the full set of SSB IDs. TheDCI/MAC-CE can select which RRH(s) or corresponding PCI(s) and/or SSB(s)to serve the UE 104 based on RSRP per reported SSB ID per reported PCI.In a third example, each serving cell may have one PCI. The DCI/MAC-CEcan select which serving cell(s) or corresponding serving cell ID(s) toserve the UE 104 based on RSRP per reported SSB ID per reported PCI. Theforgoing SSB concept may be extended to other cell-defining RS, e.g.CSI-RS, PRS (positioning reference signal).

The base stations 102 configured for 4G LTE (which can collectively bereferred to as Evolved Universal Mobile Telecommunications System (UMTS)Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC160 through backhaul links 132 (e.g., using an S1 interface). The basestations 102 configured for 5G NR (which can collectively be referred toas Next Generation RAN (NG-RAN)) may interface with 5GC 190 throughbackhaul links 184. In addition to other functions, the base stations102 may perform one or more of the following functions: transfer of userdata, radio channel ciphering and deciphering, integrity protection,header compression, mobility control functions (e.g., handover, dualconnectivity), inter-cell interference coordination, connection setupand release, load balancing, distribution for non-access stratum (NAS)messages, NAS node selection, synchronization, radio access network(RAN) sharing, multimedia broadcast multicast service (MBMS), subscriberand equipment trace, RAN information management (RIM), paging,positioning, and delivery of warning messages. The base stations 102 maycommunicate directly or indirectly (e.g., through the EPC 160 or 5GC190) with each other over backhaul links 134 (e.g., using an X2interface). The backhaul links 132, 134 and/or 184 may be wired orwireless.

The base stations 102 may wirelessly communicate with one or more UEs104. Each of the base stations 102 may provide communication coveragefor a respective geographic coverage area 110. There may be overlappinggeographic coverage areas 110. For example, the small cell 102′ may havea coverage area 110′ that overlaps the coverage area 110 of one or moremacro base stations 102. A network that includes both small cell andmacro cells may be referred to as a heterogeneous network. Aheterogeneous network may also include Home Evolved Node Bs (eNBs)(HeNBs), which may provide service to a restricted group, which can bereferred to as a closed subscriber group (CSG). The communication links120 between the base stations 102 and the UEs 104 may include uplink(UL) (also referred to as reverse link) transmissions from a UE 104 to abase station 102 and/or downlink (DL) (also referred to as forward link)transmissions from a base station 102 to a UE 104. The communicationlinks 120 may use multiple-input and multiple-output (MIMO) antennatechnology, including spatial multiplexing, beamforming, and/or transmitdiversity. The communication links may be through one or more carriers.The base stations 102/UEs 104 may use spectrum up to Y MHz (e.g., 5, 10,15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrieraggregation of up to a total of Yx MHz (e.g., for x component carriers)used for transmission in the DL and/or the UL direction. The carriersmay or may not be adjacent to each other. Allocation of carriers may beasymmetric with respect to DL and UL (e.g., more or less carriers may beallocated for DL than for UL). The component carriers may include aprimary component carrier and one or more secondary component carriers.A primary component carrier may be referred to as a primary cell (PCell)and a secondary component carrier may be referred to as a secondary cell(SCell).

In another example, certain UEs 104 may communicate with each otherusing device-to-device (D2D) communication link 158. The D2Dcommunication link 158 may use the DL/UL WWAN spectrum. The D2Dcommunication link 158 may use one or more sidelink channels, such as aphysical sidelink broadcast channel (PSBCH), a physical sidelinkdiscovery channel (PSDCH), a physical sidelink shared channel (PSSCH),and a physical sidelink control channel (PSCCH). D2D communication maybe through a variety of wireless D2D communications systems, such as forexample, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi accesspoint (AP) 150 in communication with Wi-Fi stations (STAs) 152 viacommunication links 154 in a 5 GHz unlicensed frequency spectrum. Whencommunicating in an unlicensed frequency spectrum, the STAs 152/AP 150may perform a clear channel assessment (CCA) prior to communicating inorder to determine whether the channel is available.

The small cell 102′ may operate in a licensed and/or an unlicensedfrequency spectrum. When operating in an unlicensed frequency spectrum,the small cell 102′ may employ NR and use the same 5 GHz unlicensedfrequency spectrum as used by the Wi-Fi AP 150. The small cell 102′,employing NR in an unlicensed frequency spectrum, may boost coverage toand/or increase capacity of the access network.

A base station 102, whether a small cell 102′ or a large cell (e.g.,macro base station), may include an eNB, gNodeB (gNB), or other type ofbase station. Some base stations, such as gNB 180 may operate in atraditional sub 6 GHz spectrum, in millimeter wave (mmW) frequencies,and/or near mmW frequencies in communication with the UE 104. When thegNB 180 operates in mmW or near mmW frequencies, the gNB 180 may bereferred to as an mmW base station. Extremely high frequency (EHF) ispart of the RF in the electromagnetic spectrum. EHF has a range of 30GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters.Radio waves in the band may be referred to as a millimeter wave. NearmmW may extend down to a frequency of 3 GHz with a wavelength of 100millimeters. The super high frequency (SHF) band extends between 3 GHzand 30 GHz, also referred to as centimeter wave. Communications usingthe mmW/near mmW radio frequency band has extremely high path loss and ashort range. The mmW base station 180 may utilize beamforming 182 withthe UE 104 to compensate for the extremely high path loss and shortrange. A base station 102 referred to herein can include a gNB 180.

The EPC 160 may include a Mobility Management Entity (MME) 162, otherMMES 164, a Serving Gateway 166, a Multimedia Broadcast MulticastService (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may be incommunication with a Home Subscriber Server (HSS) 174. The MME 162 isthe control node that processes the signaling between the UEs 104 andthe EPC 160. Generally, the MME 162 provides bearer and connectionmanagement. All user Internet protocol (IP) packets are transferredthrough the Serving Gateway 166, which itself is connected to the PDNGateway 172. The PDN Gateway 172 provides UE IP address allocation aswell as other functions. The PDN Gateway 172 and the BM-SC 170 areconnected to the IP Services 176. The IP Services 176 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services. The BM-SC 170 may provide functionsfor MBMS user service provisioning and delivery. The BM-SC 170 may serveas an entry point for content provider MBMS transmission, may be used toauthorize and initiate MBMS Bearer Services within a public land mobilenetwork (PLMN), and may be used to schedule MBMS transmissions. The MBMSGateway 168 may be used to distribute MBMS traffic to the base stations102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN)area broadcasting a particular service, and may be responsible forsession management (start/stop) and for collecting eMBMS relatedcharging information.

The 5GC 190 may include a Access and Mobility Management Function (AMF)192, other AMFs 193, a Session Management Function (SMF) 194, and a UserPlane Function (UPF) 195. The AMF 192 may be in communication with aUnified Data Management (UDM) 196. The AMF 192 can be a control nodethat processes the signaling between the UEs 104 and the 5GC 190.Generally, the AMF 192 can provide QoS flow and session management. UserInternet protocol (IP) packets (e.g., from one or more UEs 104) can betransferred through the UPF 195. The UPF 195 can provide UE IP addressallocation for one or more UEs, as well as other functions. The UPF 195is connected to the IP Services 197. The IP Services 197 may include theInternet, an intranet, an IP Multimedia Subsystem (IMS), a PS StreamingService, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved NodeB (eNB), an access point, a base transceiver station, a radio basestation, a radio transceiver, a transceiver function, a basic serviceset (BSS), an extended service set (ESS), a transmit reception point(TRP), or some other suitable terminology. The base station 102 providesan access point to the EPC 160 or 5GC 190 for a UE 104. Examples of UEs104 include a cellular phone, a smart phone, a session initiationprotocol (SIP) phone, a laptop, a personal digital assistant (PDA), asatellite radio, a positioning system (e.g., satellite, terrestrial), amultimedia device, a video device, a digital audio player (e.g., MP3player), a camera, a game console, a tablet, a smart device, robots,drones, an industrial/manufacturing device, a wearable device (e.g., asmart watch, smart clothing, smart glasses, virtual reality goggles, asmart wristband, smart jewelry (e.g., a smart ring, a smart bracelet)),a vehicle/a vehicular device, a meter (e.g., parking meter, electricmeter, gas meter, water meter, flow meter), a gas pump, a large or smallkitchen appliance, a medical/healthcare device, an implant, asensor/actuator, a display, or any other similar functioning device.Some of the UEs 104 may be referred to as IoT devices (e.g., meters,pumps, monitors, cameras, industrial/manufacturing devices, appliances,vehicles, robots, drones, etc.). IoT UEs may include MTC/enhanced MTC(eMTC, also referred to as CAT-M, Cat M1) UEs, NB-IoT (also referred toas CAT NB1) UEs, as well as other types of UEs. In the presentdisclosure, eMTC and NB-IoT may refer to future technologies that mayevolve from or may be based on these technologies. For example, eMTC mayinclude FeMTC (further eMTC), eFeMTC (enhanced further eMTC), mMTC(massive MTC), etc., and NB-IoT may include eNB-IoT (enhanced NB-IoT),FeNB-IoT (further enhanced NB-IoT), etc. The UE 104 may also be referredto as a station, a mobile station, a subscriber station, a mobile unit,a subscriber unit, a wireless unit, a remote unit, a mobile device, awireless device, a wireless communications device, a remote device, amobile subscriber station, an access terminal, a mobile terminal, awireless terminal, a remote terminal, a handset, a user agent, a mobileclient, a client, or some other suitable terminology.

Turning now to FIGS. 2-5, aspects are depicted with reference to one ormore components and one or more methods that may perform the actions oroperations described herein, where aspects in dashed line may beoptional. Although the operations described below in FIGS. 4 and 5 arepresented in a particular order and/or as being performed by an examplecomponent, it should be understood that the ordering of the actions andthe components performing the actions may be varied, depending on theimplementation. Moreover, it should be understood that the followingactions, functions, and/or described components may be performed by aspecially-programmed processor, a processor executingspecially-programmed software or computer-readable media, or by anyother combination of a hardware component and/or a software componentcapable of performing the described actions or functions.

Referring to FIG. 2, one example of an implementation of a node, such asbase station 102 (e.g., a base station 102 and/or gNB 180, as describedabove) may include a variety of components, some of which have alreadybeen described above and are described further herein, includingcomponents such as one or more processors 212 and memory 216 andtransceiver 202 in communication via one or more buses 244, which mayoperate in conjunction with modem 240 and/or communicating component 242for supporting inter or intra cell mobility based on a TAG per subset ofSSBs.

In an aspect, the one or more processors 212 can include a modem 240and/or can be part of the modem 240 that uses one or more modemprocessors. Thus, the various functions related to communicatingcomponent 242 may be included in modem 240 and/or processors 212 and, inan aspect, can be executed by a single processor, while in otheraspects, different ones of the functions may be executed by acombination of two or more different processors. For example, in anaspect, the one or more processors 212 may include any one or anycombination of a modem processor, or a baseband processor, or a digitalsignal processor, or a transmit processor, or a receiver processor, or atransceiver processor associated with transceiver 202. In other aspects,some of the features of the one or more processors 212 and/or modem 240associated with communicating component 242 may be performed bytransceiver 202.

Also, memory 216 may be configured to store data used herein and/orlocal versions of applications 275 or communicating component 242 and/orone or more of its subcomponents being executed by at least oneprocessor 212. Memory 216 can include any type of computer-readablemedium usable by a computer or at least one processor 212, such asrandom access memory (RAM), read only memory (ROM), tapes, magneticdiscs, optical discs, volatile memory, non-volatile memory, and anycombination thereof. In an aspect, for example, memory 216 may be anon-transitory computer-readable storage medium that stores one or morecomputer-executable codes defining communicating component 242 and/orone or more of its subcomponents, and/or data associated therewith, whenbase station 102 is operating at least one processor 212 to executecommunicating component 242 and/or one or more of its subcomponents.

Transceiver 202 may include at least one receiver 206 and at least onetransmitter 208. Receiver 206 may include hardware and/or softwareexecutable by a processor for receiving data, the code comprisinginstructions and being stored in a memory (e.g., computer-readablemedium). Receiver 206 may be, for example, a radio frequency (RF)receiver. In an aspect, receiver 206 may receive signals transmitted byat least one base station 102. Additionally, receiver 206 may processsuch received signals, and also may obtain measurements of the signals,such as, but not limited to, Ec/Io, signal-to-noise ratio (SNR),reference signal received power (RSRP), received signal strengthindicator (RSSI), etc. Transmitter 208 may include hardware and/orsoftware executable by a processor for transmitting data, the codecomprising instructions and being stored in a memory (e.g.,computer-readable medium). A suitable example of transmitter 208 mayincluding, but is not limited to, an RF transmitter.

Moreover, in an aspect, base station 102 may include RF front end 288,which may operate in communication with one or more antennas 265 andtransceiver 202 for receiving and transmitting radio transmissions, forexample, wireless communications transmitted by at least one basestation 102 or wireless transmissions transmitted by UE 104. RF frontend 288 may be connected to one or more antennas 265 and can include oneor more low-noise amplifiers (LNAs) 290, one or more switches 292, oneor more power amplifiers (PAs) 298, and one or more filters 296 fortransmitting and receiving RF signals. The antennas 265 may include oneor more antennas, antenna elements, and/or antenna arrays.

In an aspect, LNA 290 can amplify a received signal at a desired outputlevel. In an aspect, each LNA 290 may have a specified minimum andmaximum gain values. In an aspect, RF front end 288 may use one or moreswitches 292 to select a particular LNA 290 and its specified gain valuebased on a desired gain value for a particular application.

Further, for example, one or more PA(s) 298 may be used by RF front end288 to amplify a signal for an RF output at a desired output powerlevel. In an aspect, each PA 298 may have specified minimum and maximumgain values. In an aspect, RF front end 288 may use one or more switches292 to select a particular PA 298 and its specified gain value based ona desired gain value for a particular application.

Also, for example, one or more filters 296 can be used by RF front end288 to filter a received signal to obtain an input RF signal. Similarly,in an aspect, for example, a respective filter 296 can be used to filteran output from a respective PA 298 to produce an output signal fortransmission. In an aspect, each filter 296 can be connected to aspecific LNA 290 and/or PA 298. In an aspect, RF front end 288 can useone or more switches 292 to select a transmit or receive path using aspecified filter 296, LNA 290, and/or PA 298, based on a configurationas specified by transceiver 202 and/or processor 212.

As such, transceiver 202 may be configured to transmit and receivewireless signals through one or more antennas 265 via RF front end 288.In an aspect, transceiver may be tuned to operate at specifiedfrequencies such that UE 104 can communicate with, for example, one ormore base stations 102 or one or more cells associated with one or morebase stations 102. In an aspect, for example, modem 240 can configuretransceiver 202 to operate at a specified frequency and power levelbased on the UE configuration of the UE 104 and the communicationprotocol used by modem 240.

In an aspect, modem 240 can be a multiband-multimode modem, which canprocess digital data and communicate with transceiver 202 such that thedigital data is sent and received using transceiver 202. In an aspect,modem 240 can be multiband and be configured to support multiplefrequency bands for a specific communications protocol. In an aspect,modem 240 can be multimode and be configured to support multipleoperating networks and communications protocols. In an aspect, modem 240can control one or more components of UE 104 (e.g., RF front end 288,transceiver 202) to enable transmission and/or reception of signals fromthe network based on a specified modem configuration. In an aspect, themodem configuration can be based on the mode of the modem and thefrequency band in use. In another aspect, the modem configuration can bebased on UE configuration information associated with UE 104 as providedby the network during cell selection and/or cell reselection.

In an aspect, the processor(s) 212 may correspond to one or more of theprocessors described in connection with the UE in FIG. 6. Similarly, thememory 216 may correspond to the memory described in connection with theUE in FIG. 6.

Referring to FIG. 3, one example of an implementation of UE 104 mayinclude a variety of components, some of which have already beendescribed above and are described further herein, including componentssuch as one or more processors 312 and memory 316 and transceiver 302 incommunication via one or more buses 344, which may operate inconjunction with modem 340.

The transceiver 302, receiver 306, transmitter 308, one or moreprocessors 312, memory 316, applications 375, buses 344, RF front end388, LNAs 390, switches 392, filters 396, PAs 398, and one or moreantennas 365 may be the same as or similar to the correspondingcomponents of base station 102, as described above, but configured orotherwise programmed for base station operations as opposed to basestation operations.

In an aspect, the processor(s) 312 may correspond to one or more of theprocessors described in connection with the base station in FIG. 6.Similarly, the memory 316 may correspond to the memory described inconnection with the base station in FIG. 6.

Turning now to FIGS. 4 and 5, aspects are depicted with reference to oneor more components and one or more methods that may perform the actionsor operations described herein, where aspects in dashed line may beoptional. Although the operations described below in FIGS. 4 and 5 arepresented in a particular order and/or as being performed by an examplecomponent, it should be understood that the ordering of the actions andthe components performing the actions may be varied, depending on theimplementation. Moreover, it should be understood that the followingactions, functions, and/or described components may be performed byreference to one or more components of FIGS. 1, 2, 3, and/or 6, asdescribed herein, a specially-programmed processor, a processorexecuting specially-programmed software or computer-readable media, orby any other combination of a hardware component and/or a softwarecomponent capable of performing the described actions or functions.

FIG. 4 illustrates a flow chart of an example of a method 400 forwireless communication, for example, at a UE. In an example, UE 104 canperform the functions described in method 400 using one or more of thecomponents described in FIGS. 1, 3, and 6.

At block 402, the method 400 may determine to switch from a first RRH toa second RRH. In an aspect, the communicating component 342, e.g., inconjunction with processor(s) 312, memory 316, and/or transceiver 302,may be configured to determine to switch from a first RRH to a secondRRH. Thus, the UE 104, the processor(s) 312, the communicating component342 or one of its subcomponents may define the means for determining toswitch from a first RRH to a second RRH. In some aspects, switching froma first RRH to a second RRH at a cell includes communicating with thecell using beams of the second RRH and not beams of the first RRH.

At block 404, the method 400 may identify a TAG for the second RRH, theTAG associated with a TA offset, the first RRH and the second RRH areassociated with a serving cell. In an aspect, the communicatingcomponent 342, e.g., in conjunction with processor(s) 312, memory 316,and/or transceiver 302, may be configured to identify a TAG for thesecond RRH, the TAG associated with a TA offset, the first RRH and thesecond RRH are associated with a serving cell. Thus, the UE 104, theprocessor(s) 312, the communicating component 342 or one of itssubcomponents may define the means for identifying a TAG for the secondRRH, the TAG associated with a TA offset, the first RRH and the secondRRH are associated with a serving cell. In some aspects, the second RRHmay be different from the first RRH.

At block 406, the method 400 may switch from the first RRH to the secondRRH in accordance with the TAG and the associated TA offset. In anaspect, the communicating component 342, e.g., in conjunction withprocessor(s) 312, memory 316, and/or transceiver 302, may be configuredto switch from the first RRH to the second RRH in accordance with theTAG and the associated TA offset. Thus, the UE 104, the processor(s)312, the communicating component 342 or one of its subcomponents maydefine the means for switching from the first RRH to the second RRH inaccordance with the TAG and the associated TA offset.

At block 408, the method 400 may transmit, on an uplink communicationchannel, data to the second RRH. In an aspect, the communicatingcomponent 342, e.g., in conjunction with processor(s) 312, memory 316,and/or transceiver 302, may be configured to transmit, on an uplinkcommunication channel, data to the second RRH. Thus, the UE 104, theprocessor(s) 312, the communicating component 342 or one of itssubcomponents may define the means for transmitting, on an uplinkcommunication channel, data to the second RRH.

In some aspects, the first RRH may be associated with a different TAGand associated TA offset that is different from the TAG associated withthe TA offset of the second RRH.

In some aspects, the first RRH may be associated with a first subset ofRSs and the second RRH is associated with a second subset of RSs, andwherein the second subset of RSs may be associated with the TAG and thefirst subset of RSs is associated with the different TAG.

In some aspects, switching from the first RRH to the second RRH mayinclude switching from a first set of beams associated with the firstRRH to a second set of beams associated with the second RRH, the secondset of beams are quasi co-located with the second subset of RSs of theTAG.

In some aspects, the method 400 may include receiving, on a downlinkcommunication channel, DCI or a MAC CE indicating one or both of thefirst RRH or the second RRH to serve the UE.

In some aspects, the method 400 may include performing uplink TAmeasurement for both the first RRH and the second RRH, and updating theTAG and TA offset of the second RRH and the different TAG and TA offsetof the first RRH.

In some aspects, the TAG for the second RRH may correspond to a mostrecently received TAG for the second RRH.

In some aspects, the data may be transmitted on the uplink communicationchannel based on the most recently received TAG for the second RRH.

In some aspects, the RSs may correspond to at least one of a SSBreference signal, a channel state information reference signal, orpositioning reference signal.

In some aspects, the method 400 may include receiving a DCI or MAC CEindicating one or both of a number of cells or PCIs, the number of cellsor PCIs are associated with one or both of a serving cell or non-servingcell.

FIG. 5 illustrates a flow chart of an example of a method 500 forwireless communication, for example, at a network entity. In an example,a base station 102 can perform the functions described in method 500using one or more of the components described in FIGS. 1, 2, and 6.

At block 502, the method 500 may transmit, on a downlink communicationchannel, a first TA) and associated TA offset for the second RRH to aUE. In an aspect, the communicating component 242, e.g., in conjunctionwith processor(s) 212, memory 216, and/or transceiver 202, may beconfigured to transmit, on a downlink communication channel, a first TA)and associated TA offset for the second RRH to a UE. Thus, the basestation 102, the processor(s) 212, the communicating component 242 orone of its subcomponents may define the means for transmitting, on adownlink communication channel, a first TA) and associated TA offset forthe second RRH to a UE.

At block 504, the method 500 may detect a switch of the UE from thefirst RRH to the second RRH. In an aspect, the communicating component242, e.g., in conjunction with processor(s) 212, memory 216, and/ortransceiver 202, may be configured to detect a switch of the UE from thefirst RRH to the second RRH. Thus, the base station 102, theprocessor(s) 212, the communicating component 242 or one of itssubcomponents may define the means for detecting a switch of the UE fromthe first RRH to the second RRH.

At block 506, the method 500 may receive, on an uplink communicationchannel, data from the second RRH. In an aspect, the communicatingcomponent 242, e.g., in conjunction with processor(s) 212, memory 216,and/or transceiver 202, may be configured to receive, on an uplinkcommunication channel, data from the second RRH. Thus, the base station102, the processor(s) 212, the communicating component 242 or one of itssubcomponents may define the means for receiving, on an uplinkcommunication channel, data from the second RRH.

In some aspects, the method 500 may include transmitting a second TAGand associated TA offset for the second RRH to the UE followingtransmission of the first TAG.

In some aspects, detecting the switch from the first RRH to the secondRRH may include detecting the switch in accordance with the second TAGand associated TA offset for the second RRH, the second TAG andassociated TA offset corresponding to a most recent TAG.

In some aspects, the first RRH may be associated with a first subset ofRSs and the second RRH may be associated with a second subset of RSs,and wherein the second subset of RSs is associated with the TAG and thefirst subset of RSs is associated with the different TAG.

In some aspects, the RSs may correspond to at least one of a SSBreference signal, a channel state information reference signal, orpositioning reference signal.

In some aspects, the method 500 may include transmitting, on thedownlink communication channel, DCI or a MAC CE indicating one or bothof the first RRH or the second RRH to serve the UE.

In some aspects, the method 500 may include transmitting a DCI or MAC CEindicating one or both of a number of cells or PCIs, the number of cellsor PCIs are associated with one or both of a serving cell or non-servingcell.

FIG. 6 is a block diagram of a MIMO communication system 680 including abase station 102 and a UE 104. The MIMO communication system 600 mayillustrate aspects of the wireless communication access network 100described with reference to FIG. 1. The base station 102 may be anexample of aspects of the base station 102 described with reference toFIG. 1. The base station 102 may be equipped with antennas 634 and 635,and the UE 104 may be equipped with antennas 652 and 653. In the MIMOcommunication system 600, the base station 102 may be able to send dataover multiple communication links at the same time. Each communicationlink may be called a “layer” and the “rank” of the communication linkmay indicate the number of layers used for communication. For example,in a 2×2 MIMO communication system where base station 102 transmits two“layers,” the rank of the communication link between the base station102 and the UE 104 is two.

At the base station 102, a transmit (Tx) processor 620 may receive datafrom a data source. The transmit processor 620 may process the data. Thetransmit processor 620 may also generate control symbols or referencesymbols. A transmit MIMO processor 630 may perform spatial processing(e.g., precoding) on data symbols, control symbols, or referencesymbols, if applicable, and may provide output symbol streams to thetransmit modulator/demodulators 632 and 633. Each modulator/demodulator632 through 633 may process a respective output symbol stream (e.g., forOFDM, etc.) to obtain an output sample stream. Eachmodulator/demodulator 632 through 633 may further process (e.g., convertto analog, amplify, filter, and upconvert) the output sample stream toobtain a DL signal. In one example, DL signals frommodulator/demodulators 632 and 633 may be transmitted via the antennas634 and 635, respectively.

The UE 104 may be an example of aspects of the UEs 104 described withreference to FIGS. 1 and 2. At the UE 104, the UE antennas 652 and 653may receive the DL signals from the base station 102 and may provide thereceived signals to the modulator/demodulators 654 and 655,respectively. Each modulator/demodulator 654 through 655 may condition(e.g., filter, amplify, downconvert, and digitize) a respective receivedsignal to obtain input samples. Each modulator/demodulator 654 through655 may further process the input samples (e.g., for OFDM, etc.) toobtain received symbols. A MIMO detector 656 may obtain received symbolsfrom the modulator/demodulators 654 and 655, perform MIMO detection onthe received symbols, if applicable, and provide detected symbols. Areceive (Rx) processor 658 may process (e.g., demodulate, deinterleave,and decode) the detected symbols, providing decoded data for the UE 104to a data output, and provide decoded control information to a processor680, or memory 682.

The processor 680 may in some cases execute stored instructions toinstantiate a communicating component 242 (see e.g., FIGS. 1 and 2).

On the uplink (UL), at the UE 104, a transmit processor 864 may receiveand process data from a data source. The transmit processor 864 may alsogenerate reference symbols for a reference signal. The symbols from thetransmit processor 864 may be precoded by a transmit MIMO processor 666if applicable, further processed by the modulator/demodulators 654 and655 (e.g., for SC-FDMA, etc.), and be transmitted to the base station102 in accordance with the communication parameters received from thebase station 102. At the base station 102, the UL signals from the UE104 may be received by the antennas 634 and 635, processed by themodulator/demodulators 632 and 633, detected by a MIMO detector 636 ifapplicable, and further processed by a receive processor 638. Thereceive processor 638 may provide decoded data to a data output and tothe processor 640 or memory 642.

The components of the UE 104 may, individually or collectively, beimplemented with one or more ASICs adapted to perform some or all of theapplicable functions in hardware. Each of the noted modules may be ameans for performing one or more functions related to operation of theMIMO communication system 600. Similarly, the components of the basestation 102 may, individually or collectively, be implemented with oneor more ASICs adapted to perform some or all of the applicable functionsin hardware. Each of the noted components may be a means for performingone or more functions related to operation of the MIMO communicationsystem 600.

The above detailed description set forth above in connection with theappended drawings describes examples and does not represent the onlyexamples that may be implemented or that are within the scope of theclaims. The term “example,” when used in this description, means“serving as an example, instance, or illustration,” and not “preferred”or “advantageous over other examples.” The detailed description includesspecific details for the purpose of providing an understanding of thedescribed techniques. These techniques, however, may be practicedwithout these specific details. In some instances, well-known structuresand apparatuses are shown in block diagram form in order to avoidobscuring the concepts of the described examples.

Information and signals may be represented using any of a variety ofdifferent technologies and techniques. For example, data, instructions,commands, information, signals, bits, symbols, and chips that may bereferenced throughout the above description may be represented byvoltages, currents, electromagnetic waves, magnetic fields or particles,optical fields or particles, computer-executable code or instructionsstored on a computer-readable medium, or any combination thereof.

The various illustrative blocks and components described in connectionwith the disclosure herein may be implemented or performed with aspecially-programmed device, such as but not limited to a processor, adigital signal processor (DSP), an ASIC, a FPGA or other programmablelogic device, a discrete gate or transistor logic, a discrete hardwarecomponent, or any combination thereof designed to perform the functionsdescribed herein. A specially-programmed processor may be amicroprocessor, but in the alternative, the processor may be anyconventional processor, controller, microcontroller, or state machine. Aspecially-programmed processor may also be implemented as a combinationof computing devices, e.g., a combination of a DSP and a microprocessor,multiple microprocessors, one or more microprocessors in conjunctionwith a DSP core, or any other such configuration.

The functions described herein may be implemented in hardware, software,or any combination thereof. If implemented in software executed by aprocessor, the functions may be stored on or transmitted over as one ormore instructions or code on a non-transitory computer-readable medium.Other examples and implementations are within the scope and spirit ofthe disclosure and appended claims. For example, due to the nature ofsoftware, functions described above can be implemented using softwareexecuted by a specially programmed processor, hardware, hardwiring, orcombinations of any of these. Features implementing functions may alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations. Moreover, the term “or” is intended to mean an inclusive “or”rather than an exclusive “or.” That is, unless specified otherwise, orclear from the context, the phrase, for example, “X employs A or B” isintended to mean any of the natural inclusive permutations. That is, forexample the phrase “X employs A or B” is satisfied by any of thefollowing instances: X employs A; X employs B; or X employs both A andB. Also, as used herein, including in the claims, “or” as used in a listof items prefaced by “at least one of” indicates a disjunctive list suchthat, for example, a list of “at least one of A, B, or C” means A or Bor C or AB or AC or BC or ABC (A and B and C).

Computer-readable media includes both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. A storage medium may be anyavailable medium that can be accessed by a general purpose or specialpurpose computer. By way of example, and not limitation,computer-readable media can comprise RAM, ROM, EEPROM, CD-ROM or otheroptical disk storage, magnetic disk storage or other magnetic storagedevices, or any other medium that can be used to carry or store desiredprogram code means in the form of instructions or data structures andthat can be accessed by a general-purpose or special-purpose computer,or a general-purpose or special-purpose processor. Also, any connectionis properly termed a computer-readable medium. For example, if thesoftware is transmitted from a website, server, or other remote sourceusing a coaxial cable, fiber optic cable, twisted pair, digitalsubscriber line (DSL), or wireless technologies such as infrared, radio,and microwave, then the coaxial cable, fiber optic cable, twisted pair,DSL, or wireless technologies such as infrared, radio, and microwave areincluded in the definition of medium. Disk and disc, as used herein,include compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk and Blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above are also included within the scope ofcomputer-readable media.

The previous description of the disclosure is provided to enable aperson skilled in the art to make or use the disclosure. Variousmodifications to the disclosure will be readily apparent to thoseskilled in the art, and the common principles defined herein may beapplied to other variations without departing from the spirit or scopeof the disclosure. Furthermore, although elements of the describedaspects and/or embodiments may be described or claimed in the singular,the plural is contemplated unless limitation to the singular isexplicitly stated. Additionally, all or a portion of any aspect and/orembodiment may be utilized with all or a portion of any other aspectand/or embodiment, unless stated otherwise. Thus, the disclosure is notto be limited to the examples and designs described herein but is to beaccorded the widest scope consistent with the principles and novelfeatures disclosed herein.

What is claimed is:
 1. A method of wireless communication at a userequipment (UE), comprising: identifying a timing advance group (TAG) fora second remote radio header (RRH) that is different from a first RRH,the TAG associated with a timing advance (TA) offset, wherein the firstRRH and the second RRH are associated with a serving cell; switchingfrom the first RRH to the second RRH in accordance with the TAG and theassociated TA offset; and transmitting, on an uplink communicationchannel, data to the second RRH.
 2. The method of claim 1, wherein thefirst RRH is associated with a different TAG and associated TA offsetthat is different from the TAG associated with the TA offset of thesecond RRH.
 3. The method of claim 2, wherein the first RRH isassociated with a first subset of reference signals (RSs) and the secondRRH is associated with a second subset of RSs, and wherein the secondsubset of RSs is associated with the TAG and the first subset of RSs isassociated with the different TAG.
 4. The method of claim 3, whereinswitching from the first RRH to the second RRH includes: switching froma first set of beams associated with the first RRH to a second set ofbeams associated with the second RRH, wherein the second set of beamsare quasi co-located with the second subset of RSs of the TAG.
 5. Themethod of claim 2, further comprising receiving, on a downlinkcommunication channel, downlink control information (DCI) or a mediaaccess control (MAC) control element (CE) indicating one or both of thefirst RRH or the second RRH to serve the UE.
 6. The method of claim 5,further comprising: performing uplink TA measurement for both the firstRRH and the second RRH; and updating the TAG and TA offset of the secondRRH and the different TAG and TA offset of the first RRH.
 7. The methodof claim 6, wherein the TAG for the second RRH corresponds to a mostrecently received TAG for the second RRH.
 8. The method of claim 7,wherein the data is transmitted on the uplink communication channelbased on the most recently received TAG for the second RRH.
 9. Themethod of claim 3, wherein the first subset of RSs and the second subsetof RSs correspond to at least one of a synchronization signal block(SSB) reference signal, a channel state information reference signal, orpositioning reference signal.
 10. The method of claim 1, furthercomprising receiving a downlink control indication (DCI) or media accesscontrol (MAC) control element (CE) indicating one or both of a number ofcells or physical cell identifier (PCIs), wherein the number of cells orPCIs are associated with one or both of a serving cell or non-servingcell.
 11. A method of wireless communication at a serving cell having afirst remote radio header (RRH) and a second RRH, comprising:transmitting, on a downlink communication channel, a first timingadvance group (TAG) and associated timing advance (TA) offset for thesecond RRH to a user equipment (UE); detecting a switch of the UE fromthe first RRH to the second RRH; and receiving, on an uplinkcommunication channel, data from the second RRH.
 12. The method of claim11, further comprising transmitting a second TAG and associated TAoffset for the second RRH to the UE following transmission of the firstTAG.
 13. The method of claim 12, wherein detecting the switch from thefirst RRH to the second RRH includes detecting the switch in accordancewith the second TAG and associated TA offset for the second RRH, thesecond TAG and associated TA offset corresponding to a most recent TAG.14. The method of claim 12, wherein the first RRH is associated with afirst subset of reference signals (RSs) and the second RRH is associatedwith a second subset of RSs, and wherein the second subset of RSs isassociated with the first TAG and the first subset of RSs is associatedwith the second TAG.
 15. The method of claim 14, wherein the firstsubset of RSs and the second subset of RSs correspond to at least one ofa SSB reference signal, a channel state information reference signal, orpositioning reference signal.
 16. The method of claim 11, furthercomprising transmitting, on the downlink communication channel, downlinkcontrol information (DCI) or a media access control (MAC) controlelement (CE) indicating one or both of the first RRH or the second RRHto serve the UE.
 17. The method of claim 11, further comprisingtransmitting a downlink control indication (DCI) or media access control(MAC) control element (CE) indicating one or both of a number of cellsor physical cell identifier (PCIs), wherein the number of cells or PCIsare associated with one or both of a serving cell or non-serving cell.18. An apparatus for wireless communication, comprising: a transceiver;a memory configured to store instructions; and at least one processorcommunicatively coupled with the transceiver and the memory, wherein theat least one processor is configured to: identify a timing advance group(TAG) for a second remote radio header (RRH) that is different from afirst RRH, the TAG associated with a timing advance (TA) offset, whereinthe first RRH and the second RRH are associated with a serving cell;switch from the first RRH to the second RRH in accordance with the TAGand the associated TA offset; and transmit, on an uplink communicationchannel, data to the second RRH.
 19. The apparatus of claim 18, whereinthe first RRH is associated with a different TAG and associated TAoffset that is different from the TAG associated with the TA offset ofthe second RRH.
 20. The apparatus of claim 19, wherein the first RRH isassociated with a first subset of reference signals (RSs) and the secondRRH is associated with a second subset of RSs, and wherein the secondsubset of RSs is associated with the TAG and the first subset of RSs isassociated with the different TAG.
 21. The apparatus of claim 20,wherein to switch from the first RRH to the second RRH, the at least oneprocessor is further configured to: switch from a first set of beamsassociated with the first RRH to a second set of beams associated withthe second RRH, wherein the second set of beams are quasi co-locatedwith the second subset of RSs of the TAG.
 22. The apparatus of claim 19,wherein the at least one processor is further configured to receive, ona downlink communication channel, downlink control information (DCI) ora media access control (MAC) control element (CE) indicating one or bothof the first RRH or the second RRH to serve the UE.
 23. The apparatus ofclaim 22, wherein the at least one processor is further configured to:perform uplink TA measurement for both the first RRH and the second RRH;and update the TAG and TA offset of the second RRH and the different TAGand TA offset of the first RRH.
 24. The apparatus of claim 23, whereinthe TAG for the second RRH corresponds to a most recently received TAGfor the second RRH, and wherein the data is transmitted on the uplinkcommunication channel based on the most recently received TAG for thesecond RRH.
 25. The apparatus of claim 19, wherein the first subset ofRSs and second subset of RSs correspond to at least one of asynchronization signal block (SSB) reference signal, a channel stateinformation reference signal, or positioning reference signal.
 26. Anapparatus having a first remote radio header (RRH) and a second RRH forwireless communication, comprising: a transceiver; a memory configuredto store instructions; and at least one processor communicativelycoupled with the transceiver and the memory, wherein the at least oneprocessor is configured to: transmit, on a downlink communicationchannel, a first timing advance group (TAG) and associated timingadvance (TA) offset for the second RRH to a user equipment (UE); detecta switch of the UE from the first RRH to the second RRH; and receive, onan uplink communication channel, data from the second RRH.
 27. Theapparatus of claim 26, wherein the at least one processor is furtherconfigured to transmit a second TAG and associated TA offset for thesecond RRH to the UE following transmission of the first TAG.
 28. Theapparatus of claim 27, wherein to detect the switch from the first RRHto the second RRH, the at least one processor is further configured todetect the switch in accordance with the second TAG and associated TAoffset for the second RRH, the second TAG and associated TA offsetcorresponding to a most recent TAG.
 29. The apparatus of claim 27,wherein the first RRH is associated with a first subset of referencesignals (RSs) and the second RRH is associated with a second subset ofRSs, and wherein the second subset of RSs is associated with the firstTAG and the first subset of RSs is associated with the second TAG. 30.The apparatus of claim 29, wherein the first subset of RSs and thesecond subset of RSs correspond to at least one of a SSB referencesignal, a channel state information reference signal, or positioningreference signal.